Abstract: A method for obtaining an aromatic polyamide crumb from an aromatic diamine and an aromatic diacid chloride, which aromatic polyamide comprises 5(6)-amino-2-(p-aminophenyl)benzimidazole terephthalamide units and has a relative viscosity ?rel of at least 3, by: (1) adding at least monomers (i)-(iii) in N-methyl pyrrolidone as solvent wherein (i) is 0-30 mole % para-phenylenediamine (PPD), (ii) is 20-50 mole % 5(6)-amino-2-(p-aminophenyl)benzimidazole (DABPI), (iii) is 49.05-50.05 mole % terephthaloyl dichloride (TDC), and optionally calcium chloride to obtain a CaCl2/aromatic diamine molar ratio less than 0.5, and an aromatic diamine/aromatic diacid chloride ratio between 0.99 and 1.01; (2) mixing the monomers and the optional calcium chloride to a homogenous mixture having a monomer concentration of 5 to 12 wt %; followed by (3) adding calcium chloride to the homogeneous mixture to obtain a CaC12/aromatic diamine molar ratio 0.6-1.0; and (4) polymerizing the mixture.

Abstract: A method for obtaining an aromatic polyamide crumb from an aromatic diamine and an aromatic diacid chloride, which aromatic polyamide comprises 5(6)-amino-2-(p-aminophenyl)benzimidazole terephthalamide units and has a relative viscosity ?rel of at least 3, by: (1) adding at least monomers (i)-(iii) in N-methyl pyrrolidone as solvent wherein (i) is 0-30 mole % para-phenylenediamine (PPD), (ii) is 20-50 mole % 5(6)-amino-2-(p-aminophenyl)benzimidazole (DABPI), (iii) is 49.05-50.05 mole % terephthaloyl dichloride (TDC), and optionally calcium chloride to obtain a CaCl2/aromatic diamine molar ratio less than 0.5, and an aromatic diamine/aromatic diacid chloride ratio between 0.99 and 1.01; (2) mixing the monomers and the optional calcium chloride to a homogenous mixture having a monomer concentration of 5 to 12 wt %; followed by (3) adding calcium chloride to the homogeneous mixture to obtain a CaCl2/aromatic diamine molar ratio 0.6-1.0; and (4) polymerizing the mixture.